Head Coach Phil Neville telephoned the 19-year-old to tell her the news himself - and it moved her to tears.
Hampton has been included in Neville's squad for the SheBelieves Cup in America as a training 'keeper.
Nonetheless, it is a huge step towards a full England cap for Hampton, who earned her first Under-21s recognition in August.
"It was all a bit unreal, to be honest," Hampton recalled. "I questioned him quite a lot of times: 'are you sure?'
He said 'we'd like to bring you in the squad for training' and then asked me if I was all right!
"I think I cried over the phone, I couldn't believe it. It's a dream come true.
"I just want to go there and do well and prove myself.
"Being in the senior environment, you are around top players every day.
"It is going to be a great experience and will help show me what I need to do to get there and maintain it, for future call ups."
Neville has Ellie Roebuck, Carly Telford and Sandy MacIver as his three frontline 'keepers for the tournament, held between 5 - 11 March. But Hampton's inclusion shows she is breathing down their necks and just how highly regarded she is in the national programme.
Ironically, Hampton also feels that she hasn't quite been at her top level this season. That is something which annoys her.
"I have said to everyone who has asked me that my performances this year have been nowhere near where I expected them to be.
"It is something I am working on. I know I can do a lot better than I have been.
"So the call up came as a shock in that respect.
"I set my standards high. I can be better, I know that."
Alex Brooks took over in goal for Blues FA Cup win at Sunderland last weekend as Marta Tejedor rotated the team.
Hampton is expected back between the sticks for Sunday's crucial home game against Bristol City at Solihull Moors (2pm).
It's another big game for Blues and Hampton says rather than worry about the pressure of the situation, it is best to embrace it.
"I thrive on pressure rather than let it get me the other way.
"The team in general are looking forward to the challenge.
"We know it is a must win game, so do Bristol, and they are going to come out with that attitude.
"If we get points out of the game we can build on it, I am sure, and move up the table.
"When we went to Bristol they showed great resilience when they went 1-0 down to try and get back into the game. When we put our second goal in we kind of finished them off.
"If we can do that again, earlier, then hopefully it will be easier for us. But nothing is taken for granted."
Hampton says that it's as if Blues are starting over once more.
After bedding in new players following the summer overhaul, injuries bit hard.
"You can't really put our league position down to those kind of things as excuses.
"We have just got to work hard and do the best we can with the situation we are in.
"I think, yes, it has been frustrating that we haven't had all our players and we've had to bring the kids in. But the kids have stepped up to the mark. They have proven themselves in and around the team.
"It has just been hard in general that we are a brand new team and we have had to gel. Then with all the injuries it's set us back and we've had to start all over again.
But the work we are all putting in is beginning to show in our performances. We have been proving we are tough to play against and break through."
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